With advancements in science and technology, traditional linear control methods have shorts in meeting the demands of high-frequency, high-power, and high-precision control. Consequently, the application of high-performance nonlinear control methods in power electronics has emerged as a critical concern. The paper proposed a hybrid sliding mode control for bidirectional Buck-Boost converter. In Buck mode, a state observer combined with hysteresis loop sliding mode control reduces switching frequency and sensor dependency. In Boost mode, non-singular terminal sliding mode control addresses the singular phenomena in sliding mode control, compensating for the non-minimum phase disadvantages of the Boost converter. Simulation results confirm that the proposed control method enhances both dynamic and steady-state characteristics. Furthermore, the control strategy is easy to adjust parameters and implementation, offering a novel approach for power electronic converter design and application.